Patent DE-102012204551-A1 (DE)
Title: Preparing template comprising substrate and crystal layer made of e.g. aluminum nitride, comprises e.g. performing crystal growth of material on substrate at crystal growth temperature, changing to second temperature and continuing growth
Inventor: GRUENDER MARIT
IPC: C30B25/18
Filed: 2012-03-21
Abstract: Preparing a template comprising a substrate and at least one crystal layer made of nitrides of at least one element of the third main group, preferably aluminum, gallium and indium, comprises: (a) providing a substrate; (b) performing crystal growth of a material comprising nitrides of at least one element of the third main group, preferably aluminum, gallium and indium on the first substrate at a crystal growth temperature; (c) changing the temperature to a second temperature; (d) continuing the crystal growth to form a crystal in a region modified with respect to first growth temperature. Preparing a template comprising a substrate and at least one crystal layer made of nitrides of at least one element of the third main group, preferably aluminum, gallium and indium, comprises: (a) providing a substrate; (b) performing crystal growth of a material comprising nitrides of at least one element of the third main group, preferably aluminum, gallium and indium on the first substrate at a crystal growth temperature; (c) changing the temperature to a second temperature, which is modified compared to the first crystal growth temperature such the crystal growth can take place; (d) continuing the crystal growth to form a crystal comprising nitrides of at least one element of the third main group, preferably aluminum, gallium and indium in a region the modified with respect to the first growth temperature, where the second temperature in the step (c) is lower than the first temperature and the crystal growth is continued under the first growth temperature in step (d), when the substrate used has a higher thermal expansion coefficient than the crystal growing in the step (d), or the second temperature in the step (c) is higher than the first temperature and the crystal growth is continued under the first growth temperature in the step (d), when the substrate used has a lower thermal expansion coefficient than the crystal growing in the step (d). Independent claims are also included for: (1) producing a single crystal comprising nitrides of at least one element of the third main group, preferably aluminum, gallium and indium, comprising carrying out the above mentioned steps (a)-(d), (e) performing additional epitaxial crystal growth for the formation of the crystal at a crystal growth temperature, which is independent of the first and second temperatures, and f) optionally separating the formed single crystal and substrate, and (a1) providing a template comprising a third substrate and at least one crystal layer comprising nitrides of at least one element of the third main group, preferably aluminum, gallium and indium, where the template is not curved in the temperature of an epitaxial crystal growth, or substantially negatively curved, (b1) performing an epitaxial crystal growth of the crystal at crystal growth temperature, (c1) optionally performing additional epitaxial crystal growth for the formation of the crystal at a crystal growth temperature which is independent from the the crystal growth temperature of step (b1), where optionally the step (c1) is included and (d1) optionally further separating of the single crystal and substrate, and separating the crystal to form wafer; and (2) a single crystal comprising nitrides of at least one element of the third main group, preferably aluminum, gallium and indium, which is adhered to another substrate.